1. Technical Field
The present invention relates to a virtual image display device for presenting a video to an observer as a virtual image, and in particular to a virtual image display device suitable for a head-mounted display to be mounted on the head of the observer.
2. Related Art
There have been proposed a variety of systems as an optical system to be incorporated in the virtual image display device such as the head-mounted display (hereinafter also referred to as an HMD) to be mounted on the head of the observer (see, e.g., JP-A-2011-2753 (Document 1) and JP-A-2010-145859 (Document 2)).
Regarding the virtual image display device such as an HMD, it is desired that miniaturization and weight reduction are progressed and that a wider field angle is achieved without degrading the image quality. Further, in the case of covering the entire sight of the observer to make the state in which only the video light can be seen, the observer fails to understand the external state, and thus feels unsafe. By showing the external sight and the video superimposed with each other, a new usage such as virtual reality is rather generated. Therefore, there is desired a display, which displays the video light in a superimposed manner without hindering the external sight. Further, in order to improve the wearing feeling of the observer, and to improve the appearance shape, it is generally desired to approach the shape of a pair of glasses.
Taking the above circumstances into consideration, it is possible to configure the virtual image display device with, for example, a light guide device disposed in front of the eyes of the observer in a see-through manner to guide the video light from the image display element to the eyes of the observer via such a see-through type light guide device. In the virtual image display device of this kind, it is necessary to hold the light guide device in front of the eyes, and there is an example in which a pair of image display sections each including an image light generation device and a light guide plate are fixed to a coupling member, and the coupling member is fixed to the back of a frame similar to frames of a pair of glasses (see Document 1).
However, in the virtual image display device described in Document 1, no consideration is given to the observer wearing a pair of glasses. Specifically, it is not assumed that the pair of glasses are disposed between the light guide plate and the eyes, and there is a possibility that the light guide plate interferes with, for example, the lenses or the nose pad of the pair of glasses.